Avalanche Forecast
Issued: Apr 20th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Cornices and Persistent Slabs.
Ian Jackson,
Good travel conditions exist right now with dry snow on high north aspects. Start and finish your trips early to take advantage of lower avalanche danger in the mornings
Summary
Weather Forecast
Wednesday looks like another beautiful day to be in the mountains. Clear skies, a good freeze and slightly warmer than Tuesday. Winds are forecast to increase to moderate from the NW throughout the day and bring some clouds by afternoon. Thursday and Friday are looking to be cool with light snow and light winds.
Snowpack Summary
Dry snow exists above 2200 m on north aspects, but has been cooked by the sun on solar aspects where multiple crusts exist in the snowpack. Persistent layers in the mid and lower snowpack were re-activated in a few instances during the heating last week producing large avalanches with large loads (cornice failures and explosives).
Avalanche Summary
Some loose wet activity was observed as the day warmed up, but overall, much less than during last weeks warmup.
Confidence
Problems
Loose Wet
Clear skies mean solar aspects will start sluffing as the day warms up. These will start small as just the new snow sluffs and gradually get bigger as the surface crusts break down.
- Travel early before the heat of the day.
- Use extra caution on solar slopes or if the snow is moist or wet.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are unpredictable even to experienced forecasters. However, we do know that they are big right now and will fall off sometime before summer. Some cornices failures last week were enough to trigger the persistent weak layers.
- Give cornices a wide berth when travelling on or below ridges.
- Cornices become weak with daytime heating, so travel early on exposed slopes.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Persistent Slabs
Cooler temperatures may decrease the likelihood of deeper layers in the mid to lower snowpack being triggered. If there is a poor freeze or one of the many large cornices fails, larger avalanches on these layers are still a possibility.
- Pay attention to overhead hazards like cornices which could trigger persistent slabs.
- Pockets of persistent slabs linger on alpine lee features.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 21st, 2021 4:00PM
